Log Home Caulk & Sealant

Log Home Caulk & Sealant

Logs are in constant motion — expanding, contracting, settling, and checking as the seasons and moisture levels change. That movement opens gaps, cracks, and checks that let in water, air, and insects. The right log home caulk and sealant flexes with your logs to keep that seal tight for years. At Wasatch Timber, we carry the Sashco sealant line built specifically for log structures, including Log Builder, Conceal Textured Caulk, Big Stretch, and the backer rod you need behind every joint.

Which Sealant Is Right for Your Job?

Log Builder is the sealant made for log structures. It stretches up to 500% of its original size while keeping a tenacious bond to the wood, making it ideal for checks, cracks, and joints in log walls. Conceal Textured Caulk is formulated to disappear into the woodwork — its textured finish blends seamlessly so you can't tell where the wood ends and the caulk begins, perfect for a natural look. Big Stretch is a high-performance elastomeric sealant for general gaps around the home: trim, baseboard, crown moulding, and siding.

Behind every joint, backer rod does the quiet but critical work: it controls how deep the sealant sits, prevents three-sided adhesion, and lets the caulk stretch properly as logs move. Skipping backer rod is the most common reason sealant fails early.

When to Caulk Your Log Home

Because most logs move significantly in the first few years after construction due to moisture loss and shrinkage, it's important to caulk early with a product designed to move with them. On a first finish, the general best practice is to stain first and caulk last — the stain acts as a primer that helps the sealant adhere and adds a protective barrier behind the joint.

Frequently Asked Questions

What's the difference between caulk and chinking?
Caulk and sealant are for narrower gaps, checks, and cracks — typically under 1 inch. Chinking is for the wide joints between logs and creates the signature textured mortar look. Many log homes use both.

How much sealant do I need?
Measure the total linear feet of gaps and the average gap width and depth. Tube and bulk coverage varies with joint size, so estimate generously and keep extra on hand.

Can I caulk over old caulk?
Only if the existing sealant is clean, sound, and well-bonded. Remove any cracked, peeling, or failing material first.

Do I really need backer rod?
Yes, for most joints. It sets the proper depth and prevents the sealant from bonding to the back of the joint, which is what allows it to stretch as your logs move.

Not sure which sealant fits your project? Get a free quote and we'll help you spec it.